A lidar sensor is a light detection and ranging sensor. It is an optical remote sensing module that can measure the distance to a target or objects in a landscape, by irradiating the target or landscape with light, using pulses from a laser, and measuring the time it takes photons to travel to said target or landscape and return after reflection to a receiver in the lidar module. Lidar sensors based on mechanical motion achieve a wide field of view. The cost and resolution of mechanical-motion lidar sensors containing multiple discrete individually packaged lasers are not optimal, as having a plurality of individually-packaged lasers is costly and scanning the environment in planes defined by individual collimated lasers does not achieve an acceptable resolution in some applications, especially ones where the lidar mounting platform is static (e.g., on a pole for use in road/intersection/traffic monitoring) or when the lidar mounting platform is generally mobile but has scenarios where it is static (e.g., a vehicle stopped at a traffic light that needs to sense pedestrians across the intersection, a situation where it cannot benefit from the laser beam sweeping obtained when the vehicle is moving/shaking/vibrating).
U.S. Pat. No. 5,455,669 discloses a laser range finding apparatus comprising a mirror mounted for rotation along a vertical axis parallel to the vertical axis of light from a pulsed laser being emitted for deflection into the measurement region, and angularly inclined with respect to the plane of rotation and the vertical axis to cause pulsed light from the collimated laser to be diverted over the planar measurement field and reflected light from the measurement region to be received from the planar measurement region and diverted along a vertical path to a photoreceiver arrangement.
U.S. Pat. No. 7,746,449 discloses a light detection and ranging system, comprising a collimated laser beam, a mirror unit rotating around a scan axis, the mirror unit including a receiving portion and a transmitting portion offset by an angle about the scan axis relative to a surface plane of the receiving portion, respective centroids of the receiving and transmitting portions being positioned at a common point on the scan axis.
U.S. Pat. No. 7,969,558 discloses a lidar-based 3-D point cloud system comprising a support structure, a plurality of laser emitters supported by the support structure, a plurality of avalanche photodiode detectors supported by the support structure, and a rotary component configured to rotate the plurality of laser emitters and the plurality of avalanche photodiode detectors at a speed of at least 200 RPM (rotations per minute).
US application 2011/0216304 discloses a LiDAR-based sensor system comprising a base, head assembly, a rotary component configured to rotate the head assembly with respect to the base, the rotation of the head assembly defining an axis of rotation; an electrical motherboard carried in the head assembly, the motherboard defining a plane and being positioned substantially parallel to the axis of rotation, a plurality of photon transmitters mounted to a plurality of emitter circuit boards, the plurality of emitter circuit boards being mounted directly to the motherboard, and a plurality of detectors mounted to a plurality of detector circuit boards, the plurality of detector circuit boards being mounted directly to the motherboard.